Zhang Zhijin, Wang Bingbing, Li Xuze, Jing Shude, Gao Yuan, Zeng Dong, Jiang Xingliang
Xuefeng Mountain Energy Equipment Safety National Observation and Research Station, Chongqing University, Chongqing 400044, China.
Polymers (Basel). 2024 Jul 8;16(13):1944. doi: 10.3390/polym16131944.
Composite insulators have been widely used in power grids due to their excellent electrical-external-insulation performance. Long-term operation at high voltage levels accelerates the aging of composite insulators; however, there is a scarcity of research on aged composite insulators operating at 500 kV for over ten years. In this paper, the mechanical, electrical, and microscopic properties were tested on different sheds along a 500 kV composite insulator that had been running for 18 years. Additionally, the results were compared with a new insulator and the standards for live insulator operation. The results showed that the aging of the high-voltage end of composite insulators was the most serious. The results of the physical properties test indicated that the insulator's hardness was compliant but its tensile strength and break elongation did not meet standards. Under wet conditions, the pollution flashover voltage decreases by about 50% compared to the new insulator. Combined with the microscopic test results, the shed skeleton structure could be damaged and the filler might be lost during the aging process of polydimethylsiloxane (PDMS). The hardness of the insulator would increase by the precipitation of inorganic silicon; however, inorganic silicon might destroy the hydrophobicity and other properties of insulator sheds. These results can provide theoretical references for insulator life prediction and operation protection.
由于其优异的电气外绝缘性能，复合绝缘子已在电网中广泛应用。在高压等级下长期运行会加速复合绝缘子的老化；然而，对于运行超过十年的500kV老化复合绝缘子的研究却很匮乏。本文对运行了18年的500kV复合绝缘子不同伞裙进行了机械、电气和微观性能测试。此外，还将测试结果与新绝缘子以及运行中绝缘子的标准进行了比较。结果表明，复合绝缘子高压端的老化最为严重。物理性能测试结果表明，该绝缘子硬度合格，但其拉伸强度和断裂伸长率未达标。在潮湿条件下，与新绝缘子相比，污闪电压降低约50%。结合微观测试结果，在聚二甲基硅氧烷（PDMS）老化过程中，伞裙骨架结构可能受损，填料可能流失。绝缘子的硬度会因无机硅的析出而增加；然而，无机硅可能会破坏绝缘子伞裙的憎水性和其他性能。这些结果可为绝缘子寿命预测和运行保护提供理论参考。
